M50 Upgrade Contact 1
Client: South Dublin County Council
Engineer: Arup
Value: circa 200 million euro
Period: March 2006 - April 2009


SIAC was awarded the M50 Upgrade Contract 1 in a joint venture with Ferrovial Agroman Ireland in December 2005. The original scope of works included the construction of an additional running lane and auxiliary lane along 7.5km of the M50 motorway and the upgrade of the N4, N7 and Ballymount interchanges.
A substantial variation was subsequently issued by the client that amended the scope of works at the N7 interchange to provide a free flow interchange at the Red Cow junction. The M50 upgrade, including this variation, involved the construction of 12 new road bridges, 4 new pedestrian overbridges and the upgrade of 6 existing bridges spanning the M50. It also included the construction of the Monastery Road signature bridge over the N7. The works at the N7 interchange necessitated the construction of 750m of twin Luas track and a new tram stop at the Red Cow park and ride station. The daily traffic flows on the M50 during construction were in excess of 100,000 vehicles a day. The M50 N7 junction is considered one of the busiest along the M50. The works progressed on at the N7 without affecting the traffic flows.

 Summary numbers:

  • 7.85km of mainline, 12.5km of on and off slip roads, including roadways at junctions
  • Interchanges: N4 junction (3 road bridges, 2 pedestrian footbridges, 8 retaining walls): N7 junction (10 road bridges, 2 pedestrian footbridges,11 retaining walls);  Ballymount  (1 road bridge, 3 retaining walls)
  •  780,000m3 of material excavated
  •  280,000m3 of fill, capping and sub-base
  •  500,000m3 of material disposed off site (This equates to over 60,000 truck loads)
  • 45km of drainage installed (carrier, filter and slot drain)
  • 200km of ducting installed
  • 160,000m3 of blacktop placed
  •  800m Luas diversion and the construction of a new park and ride facility at the Red Cow
  • 500 people on site at any time during construction
  • 30km of temporary safety barrier utilised during construction.